My opinion is yes, but...

Yes, the seats are better.

Yes, you get personal videos.

Yes, you get to access the Flagship lounges.

Yes, you get caviar.

Yes, you get hot fudge on your ice cream.

But, suprisingly to me:

With the exception of the caviar and the fudge, the food and wine are exactly the same (including the ice cream). I find this irritating .

Second, the P seats -- unless you get a new flat seat which is still rare -- are only so so...and some of the planes have upgraded C seats with a 61" pitch w/o having upgraded the P seats.

So, some of the decision comes down to time of day: I wouldn't be as inclined to upgrade on a breakfast flight (I do like the caviar), and if I planned to work, I wouldn't care that much about the videos. In addition, the seat difference is only "really" relevant on a late afternoon/red-eye flight, when/if you plan on sleeping.